# include <stdio.h>
#include <math.h>
int main()
{
    float month = 0.0;
    int d = 300000;
    int p = 6000;
    float r = 0.01;
    month = (log(p) - log(p -d *r))/log(1+r);
    printf("%.1f\n", month);
    return 0;
}